This present disclosure relates to retrofit window insulation systems, specifically windows that are added to existing windows and window frames. A significant amount of effort and attention are spent towards increasing the thermal insulating properties of existing windows, as that is a primary source of energy loss in a building. Existing technologies focus on the window pane (by increasing the number or thickness of panes, inert gas, and coatings), but completely neglect the frame. The frame in most office windows is made from aluminum, an excellent conductor of heat. An improved retrofit window solution is needed.